Wicking instrument for LASIK surgery

ABSTRACT

An apparatus and method are provided for use in removing liquid from under a corneal flap generated during LASIK surgery. The apparatus comprises a handle, a sickle-shaped end coupled to the handle, the sickle-shaped end having a concave and a convex portion, and a sponge coupled with the concave portion of the sickle-shaped end, extending along the convex portion thereof, and being shaped substantially similarly to the sickle-shaped end. The sickle-shaped end extends from approximately 180° to 270°, or any other desired part of a circle and may have sponge on one or both sides thereof. The radius of the sickle-shaped end is the same or slightly larger than the diameter of a corneal flap generated during LASIK surgery so that when the apparatus is placed adjacent the cornea of a patient about the corneal flap, liquid is wicked from thereunder without requiring any contact with the corneal flap.

BACKGROUND OF THE INVENTION

[0001] Refractive eye surgery is a general term for a surgical procedureintended to improve or correct the focus of a patient's eyes by changingthe shape of the eye, thereby changing the optics by which the eye seesvarious images. While surgeries reshaping various portions of apatient's eye have been employed for some time, most recently,refractive eye surgery has involved reshaping the cornea of a patient'seye.

[0002] The cornea is the clear, front surface of the eye of a personwhich refracts, or bends light as it enters the eye. This light that isbent by the cornea is focused on the retina of the eye. The retina is alayer of light-sensitive cells that lines the back of the eye. Theretina converts light rays incident thereon into electrical impulses.These electrical impulses are sent through the optic nerve of the personto his or her brain. In the brain, these impulses are interpreted asimages. If images received by the eye and refracted or bent by thecornea are not properly focused on the retina, the eye is said to have arefractive error. Myopia (near-sightedness), hyperopia(far-sightedness), and astigmatism (distortion at both near and fardistances) are terms used to describe the refractive error of an eye.These refractive errors are the result of various irregular cornealcurvatures, lens curvatures, or axial eye lengths that prevent imagesfrom being focused to a single point on the eye's retina.

[0003] In performing refractive eye surgery, an excimer laser (exciteddimer) may be used to reshape the cornea, thereby enabling the cornea toproperly focus received light on the retina. The excimer laser interactswith the corneal tissue of the eye utilizing a laser-tissue interactioncalled photoablation. In photoablation, ultraviolet laser pulsesprecisely etch the cornea by uncoupling various intermolecular bondsthereof, thereby removing a submicron layer of cornea under highlycontrolled conditions. Because there is a relative absence of thermalinjury to the corneal tissue during this procedure, the corneal cellscan be ablated without opacifying (rendering so that light cannot passtherethrough) adjacent tissue. Such opacification might result in theinability to see through the opacified tissue of the eye. By carefullycontrolling the number of pulses of the ultraviolet laser, and thediameter and location of each pulse, the corneal tissue of a patient canbe resculpted as necessary in order to improve the patient's vision.

[0004] An early procedure using such an excimer laser is called PRK(photorefractive keratectomy). In this procedure, the outer surface of apatient's eye is acted upon by the laser to change the shape of thecornea. While this procedure has been quite effective in improving apatient's vision, the procedure has a number of disadvantages. Theseinclude a relatively long recovery time after the procedure, discomfortfor the patient during and after the procedure, possible infection ofthe eye after procedure, the requirement for a rigid postoperativeregimen, and a limit in the type of refractive corrections that can beperformed.

[0005] In an attempt to improve on the PRK procedure, a new procedureentitled LASIK, or laser-assisted in-situ keratomileusis has beendeveloped utilizing the excimer laser for refractive surgery. Thisvariation of the original PRK procedure has become widely accepted andis practiced by ophthalmologists worldwide. This procedure has a numberof advantages over traditional PRK, including a faster recovery time,less discomfort for the patient, a lower risk of infection, a moreconvenient post-operative regimen, and the greatest range of refractivecorrection possibilities. As a result, the LASIK procedure has surpassedPRK in the number of annual procedures performed.

[0006] The LASIK procedure involves the use of the above-noted excimerlaser for resculpting corneal tissue within the body of the cornea,known as the corneal stromal bed, as opposed to resculpting the surfaceand stroma of the cornea, as performed in the PRK procedure. In LASIK,unlike PRK, a corneal flap is created by slicing the cornea along itslamellar plane with an instrument called a microkeratome. The flapformed by this slicing, the outermost 20 percent of the thickness of thecornea, is lifted and reflected to the side. A connecting portion, orhinge between the flap and the eye remains so that the flap does notbecome completely disconnected from the remainder of the cornea. Thereflecting of this flap serves to expose the corneal stroma, or middlelayer of the corneal anatomy, to the computer-controlled laser pulseswhich reshape the corneal curvature. The excimer laser then reshapes themiddle layer of the cornea.

[0007] After the corneal stromal bed is acted upon by the excimer laser,the flap is placed back in its original position on the cornea. Thereplacement of the flap provides coverage and protection for theinternal surface of the cornea acted upon by the excimer laser. Afterthe flap has been replaced, a steady stream of fluid is introduced underthe flap, thereby momentarily “floating” the flap relative to theremainder of the cornea to eliminate any small amounts of debris thatmay be present between the flap and the remainder of the cornea as aresult of the LASIK procedure. After a sufficient amount of fluid hasbeen introduced, a milking or “squeegee” procedure follows for removingthis excess fluid from beneath the flap margins, or “gutters”. Finally,the flap gutters are further dried so as to seal and adhere the cornealflap to the remainder of the cornea. This drying is conventionallyperformed by applying merocel (PVA) sponge spears, one point at a time,to various positions around the circumferential edge of the cornealflap.

[0008] After the LASIK procedure, many patients' vision returns to anuncorrected 20/20, and occasionally even better with excellent visualimprovement over the first 24 hours. Occasionally, results are lessimpressive than expected. If there is no debris in the flap-stromainterface, and no intralamellar microfolds or wrinkles (striae) in theflap, the likelihood for an excellent result increases dramatically.Thus, a pristine initial postoperative appearance typically leads tofaster visual recovery, better visual results, and a decreased chance ofsignificant inflammatory reaction. However, the introduction of anydebris or striae under or in the flap will require the flap to be lifteda second time to avoid inflammation of the eye, generation of anirregular astigmatism, or any other compromised results. The degree offlap manipulation, or the number of times the flap must be touched,moved or contacted is directly related to the generation of flap striae.Thus, the less the flap needs to be touched, the less the chance ofstriae being generated.

[0009] A critical step in the procedure, and a step which if performedproperly greatly reduces the occurrence of striae, involves thereplacement of the flap and subsequent flap and corneal stromairrigation, drying of the space between the flap and the corneal stromaand adhesion of the flap to the corneal stroma bed. As noted above,after completion of the LASIK laser treatment, surgeons advocateirrigating between the flap and the corneal stromal bed very thoroughlyat the flap-stroma interface to eliminate any debris therefrom. Theintroduction of this irrigating solution creates a lake of fluid, asnoted above, floating the flap momentarily, so that any debris isremoved therefrom. This fluid and the hinge remaining between the flapand the corneal stroma bed also guides the flap back into properposition. After being properly replaced, as also noted above, the nextstep in the procedure involves removing the liquid from the interfacebetween the flap and the stroma of the cornea. This process is performedby milking or squeegeeing of this fluid with a moist merocel (PVA)sponge over the surface or epithelium of the cornea and corneal flap. Asponge is placed in the middle of the cornea, and is passed over thecorneal flap to the outer surface thereof to force the liquid frombeneath the flap. This process is performed a plurality of times asnecessary to remove fluid from beneath the flap. Other variations whichperform a similar function of applying pressure to the flap surface toremove fluid from under the flap include the use of a flap applanator orthe use of a corneal compressor, as is well-known in the art.

[0010] However, it is this step involving contact with the surface ofthe flap that is fraught with danger. First, any of the sponges orinstruments that are dragged across the corneal epithelium may create acorneal abrasion, and sometimes may even puncture the corneal epitheliumentirely. The result of such an abrasion or puncture of the cornea ispainful, and the eye may be prone to infection. Additionally, such anabrasion can produce unpredictable visual outcomes which are lesssuccessful than desired. In addition, whether a sponge or otherinstruments are used in this procedure, the milking process involvesdepressing the delicate corneal flap, dramatically increasing thechances of generating striae therein, or other problems with the flap,thereby further adversely affecting refractive outcome.

[0011] After the milking or squeegee process has been completed, furtherdrying is typically required circumferentially around the flap marginsto encourage adhesion of the flap to the underlying stroma of thecornea. This is customarily achieved by gently applying a dry merocelsponge spear one point at a time to the entire approximately 270° margincircumference, thereby wicking any residual fluid therefrom. This is atime-consuming, tedious process that involves multiple touches to theflap margin to remove the fluid therefrom. Because of these multipletouches to the flap, damage around the edge surface thereof, or thegeneration of striae therein are possible. Furthermore, the flap mayshift out of alignment before adhesion as a result of these touches,once again reducing the success of the refractive outcome of thesurgery. Therefore, it would be beneficial to provide a method andapparatus for removing excess liquid from under the corneal flap, whilereducing the required level of manipulation of the corneal flap anddirect contact with the corneal flap.

OBJECTS OF THE INVENTION

[0012] It is therefore an object of the invention to provide an improvedmethod and apparatus for wicking fluid from underneath a corneal flapduring the performance of a LASIK surgery procedure.

[0013] Another object of the invention is to provide an improved liquidwicking method and apparatus that removes excess liquid from under acorneal flap after LASIK surgery has been performed without coming intodirect contact with the corneal flap, and without moving the cornealflap.

[0014] A further object of the invention is to provide an improvedmethod and apparatus for insuring proper adhesion between a corneal flapand the remainder of the corneal stroma bed after LASIK surgery has beenperformed by removal of liquid from under the corneal flap until theinterface between the corneal flap and the remainder of the cornea isdry, without making contact with the corneal flap.

[0015] Still other objects and advantages of the invention will in partbe obvious and will in part be apparent from the specifications and thedrawings.

SUMMARY OF THE INVENTION

[0016] A method and apparatus, in accordance with the invention forremoving liquid from under a corneal flap replaced after LASIK surgery,is provided that allows for the removal of this liquid without contactbetween the instrument and the corneal flap. In a first embodiment, theinstrument comprises a handle with a sickle-shaped end formingapproximately 270° of a circle. One face of the sickle-shaped end of theinstrument has a merocel PVA sponge attached thereto and conforming tothe shape of the 270° sickle-shaped end of the instrument. During use,the diameter of sickle-shaped end of the instrument is provided to bethe same or slightly larger than the typical circumference of a cornealflap produced during LASIK surgery. A handle thereof may be provided atany desired angle to the plane of the sickle-shaped end of theinstrument to aid in the manipulation thereof.

[0017] After surgery, the sickle-shaped end of the instrument, includingthe merocel sponge, is placed adjacent to the cornea of a patient toform a 270° crescent just slightly larger than outside circumference ofthe corneal flap. By capillary action, liquid from under the cornealflap is drawn into the merocel sponge. In this manner, liquid can beremoved from under the corneal flap without contacting the corneal flap,thereby improving results of LASIK surgery.

[0018] In an alternative embodiment, rather than having the spongemerely conform to the sickle-shaped portion of the instrument, extendedportions of the sponge material are provided to extend across a user'sconjunctiva to allow for the removal of excess liquid. More liquid maybe removed and held by the apparatus of this alternative embodiment sothat only one instrument need be used for each eye.

[0019] In a further alternative embodiment, rather than including a 270°sickle-shaped end, the instrument of this embodiment includes asemi-circular end of approximately 180°, and is provided with a merocelsponge on either side of the semi-circular instrument substantiallyparallel to the plane thereof. Thus, the sponge on one side of thesemi-circular end of the instrument can be used for removing liquid fromunder one side of the corneal flap, and thereafter the instrument can beflipped over and the sponge on the other side of the semi-circular endof the instrument can be used to remove liquid from the other side ofthe corneal flap.

[0020] The invention accordingly comprises the several steps and therelation of one or more of such steps with respect to each of theothers, and the apparatus embodying features of construction,combinations of elements, and arrangements of parts that are adapted toeffect such steps, all as exemplified in the following detaileddisclosure, and the scope of the invention will be indicated in theclaims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0021] For a more complete understanding of the invention, reference ismade to the following description and accompanying drawings, in which:

[0022]FIG. 1 depicts an eye, along with a corneal flap and a cornealflap margin;

[0023]FIG. 2 depicts a wicking instrument constructed in accordance witha first embodiment of the invention;

[0024]FIG. 3 depicts the wicking instrument of FIG. 2 in place around acorneal flap margin;

[0025]FIG. 4 depicts a wicking instrument constructed in accordance witha second embodiment of the invention;

[0026]FIG. 5 depicts the wicking instrument of FIG. 4 in position arounda corneal flap;

[0027]FIG. 6 depicts a wicking instrument constructed in accordance witha third embodiment of the invention;

[0028]FIGS. 7A and 7B depict the wicking instrument of FIG. 6 in use onopposite sides of a corneal flap; and

[0029]FIG. 8 depicts a wicking instrument constructed in accordance withan alternative embodiment of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0030] Referring first to FIG. 1, a corneal flap generated through theperformance of LASIK surgery procedure is depicted in reference to apatient's eye. A patient's eye is shown at 100 and a colored irisportion thereof is shown at 110. 120 depicts the patient's pupil. Acorneal flap margin 130 about a corneal flap 150 is depicted as analmost complete circle extending just inside most of the iris coloredportion 110 except for a hinged portion 140. This corneal flap margin isgenerated during LASIK surgery, and hinged portion 140 maintains thecorneal flap portion in contact with the corneal stroma of the cornea110. As noted in the Background and Summary of the Invention, afterperformance of LASIK surgery, this area underneath corneal flap 150 andabove the corneal stroma of cornea 110 is irrigated with a large amountof fluid to remove any debris therefrom and for floating the cornealflap so that it may be properly placed by hinged portion 140.

[0031] Referring next to FIG. 2, an apparatus constructed in accordancewith a first embodiment of the invention is depicted, indicatedgenerally at 200. Wicking instrument 200 includes a handle portion 210,a sickle-shaped portion 220, and a highly absorbent PVA sponge portion230 positioned coextensive with, and coupled to sickle-shaped portion220. Handle or shaft 210 of the instrument is preferably formed with arounded cross-section, and includes a coarse surface at the terminal endthereof opposite end 220 to improve grip of the instrument. While inFIG. 2 the handle is shown coplanar to the shape of sickle-shaped end220, as is shown in FIG. 8, in an alternative construction it is alsopossible to position the shaft and handle portion 210 of the instrumentat a 45° angle to the plane of the sickle-shaped end 220, or at anyother angle which may be beneficial for improving ease of use of theinstrument. Additionally, this angled handle may be applied to any ofthe embodiments of the invention.

[0032] The radius of sickle-shaped portion 220 of the instrument isslightly larger or equal to the radius of corneal flap 150, taking intoaccount the width of sponge portion 230 coupled with end 220. This sizeallows for the maintenance of maximum surface contact with cornea 110,but positions sponge portion 230 just outside or at corneal flap margin130. The instrument is preferably constructed of an injected moldedsterile plastic, insuring a lightweight, disposable and sterile product.Sponge portion 230 is preferably attached to the inside, or concave edgeof sickle-shaped end 320 of wicking instrument 200, but may be attachedin any manner. The sponge continues along one side of sickle-shaped end220, coplanar thereto, and also can extend in a direction perpendicularto the plane of sickle-shaped end 220 outside, and at the convex portionthereof, if desired. The sponge is preferably composed of a highlyabsorbent wicking material such as polyvinyl alcohol (PVA) angled toconform to the shape of the peripheral cornea for maximum surfacecontact with cornea 110 and corneal flap margin 130. However, anymaterial having the features of being synthetic, biocompatible andfiber-free, thereby reducing the chance of eye infections, may be used.Materials such as PVA and the like are preferable to fibrous materialssuch as cotton gauze and cellulose in order to minimize the debris whichmight be trapped under the corneal flap. Additionally, the sponge mustbe soft enough in its dry state to provide some flexibility at its apexwhere corneal contact is initiated. This flexibility will decrease thelikelihood of flap movement upon contact of the cornea with the sponge.

[0033] The portion of the sponge at the concave or inside portion ofsickle-shaped end 220 of wicking instrument 200 is preferably formedslightly beveled or otherwise shaped, having approximately a 7.5° ofcurvature, in a preferred embodiment, so as to match the normal cornealprofile and to maximize contact of the sponge with the cornea to removethe most fluid from the corneal flap margin. The sponge is also providedat a thickness so as to maximize the absorption of excess fluid fromunder the corneal flap.

[0034] As is shown in FIG. 3, during use, wicking instrument 200 isplaced so that sickle-shaped end 220 along with highly absorbent sponge230 are positioned concentric with corneal flap margin 130 and as shownhas a radius slightly larger than that of the corneal flap margin. Theportion of sickle-shaped end 220 that is open (not the complete circle)is placed adjacent hinge 140 since it is not necessary to wick moisturetherefrom. Upon placement, liquid is wicked from under the corneal flapinto the sponge by capillary action. Through the use of this apparatusand method, it is therefore possible to wick liquid from under cornealflap 130 without making contact with the corneal flap, or squeegeeing orrolling, or risking other movement or abrasion of the corneal flap.

[0035] Referring next to FIG. 4, a wicking instrument 400 constructed inaccordance with a second embodiment of the invention is shown.Instrument 400 is provided with a handle 410, and a sickle-shaped end420 similar to those of the first embodiment. A highly absorbent PVAsponge 430 is also provided, and within the concave or inner portion ofsickle-shaped end 420 of instrument 400, is similarly shaped andsituated to the sponge in the first embodiment. However, at the outsideof concave portion of sickle-shaped end 420 of instrument 400, thesponge is provided with elongated portions 432 which conform generallyin shape and size to a patient's eye. Thus, as noted above with respectto the first embodiment, while the portion of the sponge that is totouch a user's eye is beveled or otherwise shaped with curvature tomatch the normal corneal profile of the user's eye adjacent the cornealflap, portions 432 of sponge 430 are similarly contoured and curved tofurther match the curve of a patient's eye. These elongated portions 432greatly increase the liquid-absorbing ability of the instrument.

[0036] Referring to FIG. 5, during use instrument 400 is positionedsimilarly to instrument 200 of FIG. 3. Thus, the description of FIG. 3is equally applicable to FIG. 5. The only difference being thatelongated portions 432 allow for extra absorption surfaces for removingliquid from the patient's eye, insuring that only one instrument need beused for each procedure.

[0037] Referring next to FIG. 6, a wicking instrument, indicatedgenerally at 600, constructed in accordance with a third embodiment ofthe invention is shown. In this embodiment, wicking instrument 600 isformed with a handle portion 610, a semi-circular shaped end 620 with asemi-circular shaped sponge 630 coupled therewith. Rather than thesponge only being provided on one surface of the instrument coplanar tothe end, as is shown in FIGS. 2 and 4, in this third embodiment, sponge630 is provided on both the upper and lower surfaces of thesemi-circular shaped end 620, and coplanar therewith. Thus, as is shownin FIG. 7A, during use semi-circular end 620 of instrument 600 includingsponge 630 is first placed adjacent the corneal flap margin so thatsponge 630 wicks moisture from one side of the corneal flap margin.Thereafter, as is shown in FIG. 7B, semi-circular end 620 is flippedover and is placed so that sponge 630 is positioned adjacent theopposite side of corneal flap margin 130 from that of FIG. 7A. In thismanner, both sides of the instrument are used in order to wick fluidfrom under opposite sides of corneal flap margin 130. The use of such asemi-circular shaped end may be beneficial if and when a corneal flapmargin generated is of an irregular size or shape, allowing a userperforming the wicking operation with slightly more latitude ofmovement.

[0038] Because this third embodiment must use both sides of theinstrument, in the preferred embodiment, the handle is formed coplanarwith the crescent-shaped instrument head, but may be provided with aslight angle, or a movable, changeable angle if desired.

[0039] In yet another alternative embodiment in the invention, it may bepossible to construct the instrument of a light metal or other reusablematerial that may be sterilized. The sponge is removably attachedthereto and is manufactured as a disposable attachment so that only thesponge portion need be replaced after each use.

[0040] In accordance with the invention, the uniquely shaped wickinginstruments of the invention described above provide a number ofbenefits. First, the instruments allow the replacement of the riskysqueegee step in the LASIK procedure, and also avoid the need to performmultiple wicking steps. Thus, flap adhesion can be improved bydecreasing the amount of instrument-cornea contact. Therefore, inaccordance with the invention, the currently used pushing or milkingprocess of eliminating fluid from under the corneal flap is replacedwith a gentle pulling or wicking mechanism which removes liquid bycapillary action. The invention permits efficient, evenly distributedegress of fluid from under the corneal flap, thereby simultaneouslyserving to accomplish both the drying and adhesion steps. Moreimportantly, the use of this method and apparatus significantlyminimizes corneal flap manipulation and eliminates contact with thecorneal flap surface entirely. As a result, the risk of the generationof corneal striae and abrasions are minimized accordingly. The use ofthis method apparatus of the invention will therefore lead to improvedrefractive outcomes, increased patient comfort, and healthierpost-surgical corneas.

[0041] It will thus be seen that the objects set forth above, amongthose made apparent from the preceding description, are efficientlyattained and, because certain changes may be made in carrying out theabove method and in the constructions set forth without departing fromthe spirit and scope of the invention, it is intended that all mattercontained in the above description and shown in the accompanyingdrawings shall be interpreted as illustrative and not in a limitingsense.

[0042] It is also to be understood that the following claims areintended to cover all of the generic and specific features of theinvention herein described and all statements of the scope of theinvention which, as a matter of language, might be said to falltherebetween.

What is claimed is:
 1. An apparatus for use in removing liquid fromunder a corneal flap generated during LASIK surgery, comprising: ahandle; a sickle-shaped end coupled to said handle, said sickle-shapedend having a concave and a convex portion; and a sponge coupled with theconcave portion of said sickle-shaped end, and being shapedsubstantially similarly to said sickle-shaped end.
 2. The apparatus ofclaim 1, wherein said sponge is contoured to follow the shape of acornea.
 3. The apparatus of claim 2, wherein said contour includes aradius of curvature of 7.5°.
 4. The apparatus of claim 1, wherein saidsickle-shaped end extends approximately 270%.
 5. The apparatus of claim4, wherein said sponge extends coplanar along one side of saidsickle-shaped end.
 6. The apparatus of claim 5 wherein said spongeextends in a direction perpendicular to the plane of said sickle-shapedend at the convex portion thereof, and is attached thereto.
 7. Theapparatus of claim 5, further comprising at least one elongated portionof said sponge extending coplanar with said sickle-shaped end.
 8. Theapparatus of claim 7, wherein said at least one elongated portion ofsaid sponge is contoured to follow the shape of a conjunctiva.
 9. Theapparatus of claim 4, wherein the radius of said sickle-shaped end isslightly larger than the radius of a corneal flap.
 10. The apparatus ofclaim 4, wherein said handle is formed at an angle relative to the planeof said sickle-shaped end.
 11. The apparatus of claim 10, wherein saidangle is 45°.
 12. The apparatus of claim 1, wherein said sickle-shapedend extends approximately 180°.
 13. The apparatus of claim 12, whereinsaid sponge encircles said sickle-shaped end.
 14. The apparatus of claim13, wherein said sponge is contoured at two surfaces in the plane ofsaid sickle-shaped end to follow the shape of a cornea.
 15. Theapparatus of claim 12, wherein the radius of sickle-shaped end isslightly larger than or same as a corneal flap.
 16. The apparatus ofclaim 12, wherein said handle is coupled to said sickle-shaped end at anadjustable angle.
 17. The apparatus of claim 1, wherein said sponge ispermanently fixed to said sickle-shaped end.
 18. The apparatus of claim1, wherein said sponge is removably fixed to said sickle-shaped end. 19.The apparatus of claim 1, wherein said sponge is formed of a synthetic,biocompatible, fiber-free material.
 20. A method for wicking liquid froma corneal flap generated during LASIK surgery comprising the steps of:providing a wicking instrument including a handle, a sickle-shaped endcoupled to said handle, and a sponge coupled to said sickle-shaped end;and placing one side if said sickle-shaped end and said sponge coupledthereto adjacent to a corneal flap margin of said corneal flap, therebywicking liquid from thereunder.
 21. The method of claim 20, comprisingthe steps of: flipping said sickle-shaped end; and placing another sideof said sickle-shaped end and said sponge coupled thereto adjacent tosaid corneal margin of said corneal flap.